Regulator system



Feb. 16, 1937. w. T. REA

REGULATOR SYSTEM Filed Nov. 27, 1934 fllll a, uw mf MW ATTORNEY Patented Feb. i6, 1937 UNITED STATES PATENT OFFICE i REGULATOR SYSTEM Wilton 'rma ne, Flushing, N. Y., asignar to American Telephone and Telegraph Company, a corporation of New York Application 'November 2 7, 1934, serial No. 155,064

2 Claims.

This invention relates to an improved type of.

regulator system for Vcontrolling the characteristics of a dynamo-electric device,and 'inore particularly to means for preventing the failure of 5 operation of such a device upon any failure of operation of a portion of the regulator system. In many cases it is' desirable to operate a motor at constant speed with close precision. As an Aexample of a motor which must be operated at l0' constant speed may be mentioned the motor for operating the carrier current generator in a voicefrequency carrier current sytem. 'I'he speed of the motor in the above mentioned system must be held constant with precision in order to maintain the frequency of the generated current constant. One of the regular systems utilized for controlling the speed of a motor generator device in systems .of the above mentioned type employs thermionic vacuum tubecircuits for controlling the eld excitation of a motor to maintain the speed 'thereof constant. If any of the vacuum tubes in such a motor speed control system should fail, or if the plate or filament battery supply for such tubes should fail, the regulating field current for the motor would not function properly and the speed of the motor-generator would begin to vary. In instances where the motor-generator is utilized to supply the carrier current for a voice-- frequency carrier system, it is possible that many multi-channel voice-frequency systems might be put out of service for an appreciable period of time by the .failure of a single vacuum tube or battery tap. Accordingly, it is one of the principal objects of this invention to provide arrangements whereby the speed of the motor will remain substantially constant and operative failure thereof will be prevented under conditions `where apparatus, such as the vacuum tubes, in the control circuit may fail.

Other objects and features of the invention will appear more fully from the detailed description hereinafter given.

In the arrangements of this invention centrifugally operated speed alarm device is providedv which ontmls relay transfer means in the circuit which supplies current to the regulating field of the motor. While the speed of the motor remains at a correct value, the moving member of `the speed alarm will oat between its associated contacts. 1r the vspeed regulator circuit shoum fail to operate or function properly the moving member or armature of the speed alarm will close acircuit through one of its contacts and will A thereby cause the relay means -to operate. The

operation of said relay means accomplishes circuit changes that convert the speed alarm to a double contact speed regulator which acts to control the motor speed by varying the current flowing. through the regulating field winding. IThe o net effect will be that the motor-generator will In the drawing a motor-generator system I is shown within the rectangle formed by dotted lines.' The motor-generator includes a motor 2 having a regulating field winding 3 and a shunt eld winding 4.' The motor drives an alternating current generator 5 of the inductor type. This generator includes a generating field winding 6 and an armature winding l. The batteries 8, 9, and I0 are provided for supplying current to the various windings of the motor-generator device over circuits which will be presently described.

'.The armature winding 1 is connected the winding of transformer II. which in vturn is connected to an amplifying tube I2. The output circuit of the amplifier I2 is connected to a Wheatstone bridge arrangement I3 having one arm thereof in the form of a/tuned circuit. The anti-resonant arm of the bridge circuit is tuned to the frequency developed by the generator when the motor 2 is operated at normal speed. A phase detector device I4 is provided and has an alternating. current potential impressed on the grid thereof from the bridge circuit and an alternating potential impressed upon the plate thereof from the amplifier I2. The phase relation of the potentials impressed on the grid of the phase detector tube I4 varies with respect to the po-` tentials' impressed on the plate of such tube according to the frequency of the current produced by the generatori. The phase detector tube Il is coupled to the regulating tubes I5 and I6 which inl turn are connected to a circuit including the regulating field winding 3 of the motor.

,If the motor 2 tends to increase in speed, the generator 5 is operated to raise the frequency of the generated current. The frequency bridge circuit I3 variesthe phase relation of the potential impressed upon the grid of the phase detector Il,

with respect to the .potential impressed upon lthe plate of such tube to lower the output from the phase detector tube Il. This lowers the potential drop across the. coupling resistance I1 to increase the output from the regulator amplifier tubes I5 and I6. The increased output from the regulating tubes increases the current flowv through the regulating field winding 3 to oppose the tendency of the motorA to increase in speed. If the speed of the motor tends to decrease, a. reverse action will take place in the vacuum tube tor to increase in speed.

The above arrangements for controlling or regulating the speed of a motor-generator device are well known in the art, and no further description is considered necessary. It is pointed out that in such arrangements, if any of the vacuum tubes, such as I2, I4, or I6, should fail or if their plate or lament battery should fail, the current through the regulating eld winding 3 would be reduced to zero and the motor-gen erator would gain in speed so as to be commercially' inoperative, particularly in instances where it is utilized in a voice-frequency carrier current system.

Accordingly, the arrangements of this invention provide, upon the shaft of the motor-generator, a centrifugally operated speed alarm device. This device may include a plate I9 carried by the shaft, and having an armature 20 pivotally mounted thereon. The plate is also shown as having contacts 2| and 22 mounted thereon, The armature 20 is maintained against contact 2| by spring 32 when the motor is at rest or rotating at a speed lower than normal. When the motor is rotating at a higher speed than normal, the inertia of said armature causes the tension in spring 32 to be overcome and armature 20 will rest upon contact 22. The tension of spring 32 is adjusted to such a value that it will be exactly balanced, when the motor rotating at-normal speed, by the centrifugal force of the armature 20, thereby maintaining said armature free from contacts 2| and 22.

When the motor speed is above or below normal, armature 20 will bear upon contact 22 or contact 2|, respectively, and current will ilow from battery I0 through release key 25, winding 38 of relay 23, armature 36land back contact of relay 21, conductor 20', armature 20 and contact 22 or 2|, and resistance 2 4 or 23, respectively, to ground, causing relay 2Eto operate. The operation of relay 26 permits current to flow from battery I 0 through release key 25, winding 39, front contact and armature'34 of relay 26, and winding of relay 21 to ground, thereby causing relay 21 to operate and relay 26 to be maintained in an operated condition. Armature 31 of relay 21 applies ground to alarm bell 30 causing it to give notification that the speed regulating circuit has failed. Armature 33 of relay 26 disconnects regulating Winding 3 of motor 2 from the regulating plate circuit lead I8 and connects said winding to armature 20 of speed alarm I9. Armature 36 of relay 21 disconnects the armature 20 of speed alarm I9 from winding 38 of relay 2E and connects said amature through the variable resistance 29 to ground. Armature 35 connects contact 2| of speed alarm I9 through resistance 28 topositive battery 9.

If the speed of motor 2 is now at its' normal value, current will flow from battery 9 through regulating winding 3, armature 33 of relay 26 andy its front contact, armature 36 of relay 21 and resistance 29 to ground. Resistance 29 is adjusted to such a value that said current will be approximately equal to that normally flowing through regulatingwinding 3 when the vacuum tube speed regulating circuit is operating properly.

If, however, the speedof *motor 2 is greter than normal, armature 20 willbear upon cony tact 22, causing resistance 24 to be connected in parallel with resistance 29. The current'through regulating winding 3 will be increased thereby and will oppose the tendency of the motor'speed to be greater than normal.

If the speed of motor 2 is less than normal, armature 20 Will be constrained to bear upon contact 2| causing resistance 23 to be connected in parallel with resistance 29 and resistance 28 to be shunted across regulating winding 3. The values of resistance 28 and resistance 23 are such that the current through regulatingl winding 3 will be decreased thereby to less than its normal value and the tendency of the vmotor speed to be less than normal will be opposed. The speed alarm |55,` when acting in the manner explained above, constitutes a centrifugally operated speed regulator. v

Key 25 is provided to permit the circuit to be restored to normal when it is desired to transfer the control of motor speed to the vacuum tube circuit. The operation of said key opens the holding circuit containing winding 39 and armature 34 of relay 26 and the winding of relay 21, and allows said relays to release.

While the invention has been disclosed as embodied in certain specific arrangements which are deemed desirable, it is understood that it is capable of embodiment in many and other widely varied forms without departing from the spirit of the invention as defined by the appended claims.

What is claimed is:

l. In a speed regulator system, a motor having `a regulating eld winding, a regulator circuit for controlling the excitation of said regulating eld winding to maintain the motor constant in speed, centrifugally operated alarm means responsive to a failure of said speed regulator circuit, a network adapted to Vary the current through said regulating field winding, and switch`l ing means responsive to the operation of said centrifugal alarm means, said switching means' being so arranged as to connect said network to said regulator' circuit, whereby the centrifugal alarm is caused to operate as a speed regulator to maintain the speed of said motor substantially constant over a wide range of variations of load or power voltage.

2. In a speed regulator system, a motor having `a regulating eld winding, a regulator circuit for controlling the excitation of said regulating eld winding to maintain the motor constant in speed,

centrifugally operated means responsive to a .failure of said speed regulator circuit, saidr cenlincluding a resistance element normally connected to each contact and two resistance elements normally disconnected, and switching .means responsive to the movement of the lever against the Yrespective contacts for connecting the second corresponding resistance elements toY the lever and one of the associated contacts, whereby the centrifugal means ycontrols the current in the regulating eld winding and the speed' of the motor is maintained substantially constant independently of the regulator circuit.

' WIL'l'ON TREAT REA. 

